Field of the Invention
The present invention relates to cellulolytic enzyme compositions; methods of using such cellulolytic composition for hydrolyzing acetylated cellulosic materials; and processes of producing fermentation products using cellulolytic enzyme compositions of the invention.
The conversion of cellulosic feedstocks into ethanol has the advantages of the ready availability of large amounts of feedstock, the desirability of avoiding burning or land filling the materials, and the cleanliness of the ethanol fuel. Wood, agricultural residues, herbaceous crops, and municipal solid wastes have been considered as feedstocks for ethanol production. These materials primarily consist of cellulose, hemicellulose, and lignin. Once the cellulose is converted to glucose, the glucose is easily fermented by yeast into ethanol.
The rate and extent of enzymatic hydrolysis of cellulosic material depends on various structural features such lignin content, acetyl content and crystallinity. In native plants hemicellulosic material, such as xylan, has some degree of natural acetylation, while cellulosic material (cellulose) does not. However, when cellulosic material is subjected to pretreatment with, e.g., acids, such as acetic acid, acetylation occurs. Such acetylation of cellulosic material impacts enzymatic digestibility.
WO 2005/047499 discloses an Aspergillus fumigatus beta-glucosidase and gene thereof.
WO 2006/078256 discloses Aspergillus fumigatus GH10 xylanases.
WO 2008/151079 discloses compositions for degrading cellulose material.
WO 2009/042846 disclosed an acetylxylan esterase (AXE) derived from Thielavia terrestris. 
WO 2011/041397 discloses a Penicillium sp. GH61 polypeptide having cellulolytic enhancing activity and gene thereof.
WO 2011/057140 discloses an Aspergillus fumigatus cellobiohydrolase I; Aspergillus fumigatus cellobiohydrolase II; and an Aspergillus fumigatus beta-xylosidase.
There is a need for cellulolytic enzyme compositions that can hydrolyze acetylated cellulosic materials more efficiently.